In lithography techniques, for example, a resist film composed of a resist material is formed on a substrate, and the resist film is subjected to selective exposure of radial rays such as light or electron beam through a mask having a predetermined pattern, followed by development, thereby forming a resist pattern having a predetermined shape on the resist film.
A resist material in which the exposed portions become soluble in a developing solution is called a positive-type, and a resist material in which the exposed portions become insoluble in a developing solution is called a negative-type.
In recent years, in the production of semiconductor elements and liquid crystal display elements, advances in lithography techniques have led to rapid progress in the field of pattern miniaturization.
Typically, these miniaturization techniques involve shortening the wavelength (and increasing the energy) of the exposure light source. Conventionally, ultraviolet radiation typified by g-line and i-line radiation has been used, but nowadays KrF excimer lasers and ArF excimer lasers are now starting to be introduced in mass production. Furthermore, research is also being conducted into lithography techniques that use an exposure light source having a wavelength shorter (energy higher) than these excimer lasers, such as electron beam, extreme ultraviolet radiation (EUV), and X ray.
As a method of providing a finer pattern, a method of shrinking (reducing) a hole pattern by thickening the pattern has been proposed.
For example, in Patent Document 1, a method has been described in which the amount of shrinkage of the resin is adjusted by using a fine pattern-forming resin composition containing a cross-linking agent.
Further, in Patent Document 2, a method of thickening a pattern by forming a solvent-developed negative-tone resist pattern, causing a crosslinked layer-forming material to act on the resist pattern and forming a crosslinked layer has been described.